The present invention relates in general to substrate manufacturing technologies and in particular to methods and apparatus for selective pre-coating of a plasma processing chamber.
In the processing of a substrate, e.g., a semiconductor substrate or a glass panel such as one used in flat panel display manufacturing, plasma is often employed. As part of the processing of a substrate in a plasma chamber for example, the substrate is divided into a plurality of dies, or rectangular areas, each of which will become an integrated circuit. The substrate is then processed in a series of steps in which materials are selectively removed (etching) and deposited (deposition) in order to form electrical components thereon.
In order to optimize the plasma process, many surfaces within the plasma chamber are further configured with plasma resistant materials (e.g., silicon, silicon carbide, silicon nitride, quartz, etc.) that help to minimize surface wear without substantially increasing contaminants that may, in turn, affect the substrate. However, continued exposure to the plasma sheath tends to etch away and eventually remove the protective material, often resulting in surface particle contamination and hence lower substrate yields.
Generally, the plasma sheath tends to accelerate charged particles (e.g., ions, etc.) from the plasma edge to strike surfaces in the plasma chamber. Eventually, the processing chamber surfaces may erode and thus need to be replaced in order to assure long-term stability to the plasma process. Consequently, substantial operational costs and downtime may be added to the substrate manufacturing process, depending on the chemistry, the process pressure, and the amount of power to be used to generate said plasma.
In view of the foregoing, there are desired methods and apparatus for selective pre-coating of a plasma processing chamber.